def foo():

    try:

        git.Repo.clone_from('non_existant_repo_URL',os.getcwd()+'\something')

    except:

        print('success!')

def foo():

    try:
        git.Repo.clone_from('non_existant_repo_URL',os.getcwd()+'\something')

    except <Exception or git.exc.GitError> as e:

        print('success!')

Cmd('git') failed due to: exit code(128)
  cmdline: git clone -v non_existant_repo_URL <working directory>
  stderr: 'Cloning into '<working directory>'...
remote: Repository non_existant_repo_URL not found
fatal: repository 'non_existant_repo_URL' not found